For breaking up with the price competition rat race, Chinese e-bike companies started to focus more on product differentiation by launching models of unique style and technology. In the US market more and more EU brands started to explore opportunities.

Green and yellow auto rickshaws chug through the crowded streets of New Delhi. Tuk tuks sputter on the roads in Thailand to tourists' delight.

Millions in South and Southeast Asia rely on these three wheelers -- known variously as rickshaws, tuk tuks or tricycles -- as an affordable mode of transportation. But while beloved by many, the vehicles are also blamed for bottleneck congestion and pollution, spewing carbon monoxide, carbon dioxide and particle matters that become trapped inside the lungs.

Despite America's love affair with Harley-Davidsons, electric motorcycles — as well as e-bicycles — are revving up U.S. sales.

Two-wheeled e-vehicles are gaining converts among urban commuters and law enforcement, which see a stealth advantage in their quietness. More than three dozen U.S. police departments nationwide now use e-motorcycles.